Marketable Securities and Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2017

Marketable securities, classified as available-for-sale, consisted of the following (in thousands):



	September 30, 2017									December 31, 2016
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Certificates of deposit	$	15,990	$	4	$	(1	)	$	15,993	$	12,499	$	9	$	—		$	12,508
Corporate securities	40,941		12		(13		)	40,940		42,765		9		(42		)	42,732
U.S. Treasury and agency securities	3,494		—		(12		)	3,482		5,190		—		(14		)	5,176
Commercial paper	9,214		2		—			9,216		11,470		1		(2		)	11,469
Asset-backed securities	14,352		—		(10		)	14,342		13,493		—		(6		)	13,487
	$	83,991	$	18	$	(36	)	$	83,973	$	85,417	$	19	$	(64	)	$	85,372

Schedule of Cost and Estimated Fair Values of Available-for-sale Securities by Contractual Maturity

The following table summarizes the cost and estimated fair value of marketable securities based on stated effective maturities as of September 30, 2017 (in thousands):



	Amortized Cost		Fair Value
Less than 1 year	$	59,490	$	59,480
Mature in 1 - 3 years	24,501		24,493
	$	83,991	$	83,973

Schedule of gross unrealized losses

Marketable securities in an unrealized loss position consisted of the following (in thousands):



	Less Than 12 Months					12 Months or More					Total
As of September 30, 2017	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Certificates of deposit	$	5,500	$	(1	)	$	—	$	—		$	5,500	$	(1	)
Corporate securities	27,254		(10		)	1,500		(3		)	28,754		(13		)
U.S. Treasury and agency securities	3,482		(12		)	—		—			3,482		(12		)
Asset-backed securities	14,342		(10		)	—		—			14,342		(10		)
	$	50,578	$	(33	)	$	1,500	$	(3	)	$	52,078	$	(36	)



	Less Than 12 Months					12 Months or More				Total
As of December 31, 2016	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Corporate securities	$	28,537	$	(42	)	$	—	$	—	$	28,537	$	(42	)
U.S. Treasury and agency securities	5,176		(14		)	—		—		5,176		(14		)
Commercial paper	8,974		(2		)	—		—		8,974		(2		)
Asset-backed securities	10,664		(6		)	—		—		10,664		(6		)
	$	53,351	$	(64	)	$	—	$	—	$	53,351	$	(64	)

Schedule of Cash, Cash Equivalents and Available-for-sale Investments Measured at Fair Value on Recurring Basis

The following is a summary of our cash, cash equivalents and marketable securities measured at fair value on a recurring basis (in thousands):



	September 30, 2017								December 31, 2016
	Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
Cash	$	27,346	$	—	$	—	$	27,346	$	18,672	$	—	$	—	$	18,672
Cash equivalents	12,573		—		—		12,573		10,303		—		—		10,303
Certificates of deposit	—		15,993		—		15,993		—		12,508		—		12,508
Corporate securities	—		40,940		—		40,940		—		42,732		—		42,732
U.S. Treasury and agency securities	—		3,482		—		3,482		—		5,176		—		5,176
Commercial paper	—		9,216		—		9,216		—		11,469		—		11,469
Asset-backed securities	—		14,342		—		14,342		—		13,487		—		13,487
	$	39,919	$	83,973	$	—	$	123,892	$	28,975	$	85,372	$	—	$	114,347